I've ripped out my old t&g and am redoing the framing. I am thinking to go with t&g again, but maybe decking would be more rot resistant -- thoughts? Decking would also be a lot faster, as I could run the planks parallel to the house and go with much longer boards. The porch is 6' wide -- it's covered, but not enclosed.

Is it fair to say that a maintained t&g will last as long? I'm thinking to use a latex porch paint because it's easy to work with so I'm far more likely to keep it maintained.

Any tips for assembling? Do I nail into the tongues like flooring? It looked to me like the old floor was installed with a pair of 16ga. finish nails into the top of the floor. There were no nails in the tongue. That did make removing a bit easier and I can reuse some of the old flooring.

I've heard to brush on an oil paint or preservative to all 4 sides, then apply that to the tongues when installing and finally top coat after installation. A lot of work. If I just keep the top sealed -- is that reasonable? On the PT I probably need to let that air for months if not a year -- correct?

I use Silken solid floor stain. Paint will peal and chip, stain doesn't. I nailed my through the tongues. We have to re-coat about every 4 years with the stain but don't have to scrap loose chips. I put my down and only sealed the top. It has been down for 20 years with no boards needing replacement.